Joseph Gordon-Levitt’s movie-directing debut, “Don Jon,” has the baby-faced heartthrob cast as an Italian guy from New Jersey with a severe sex addiction. Though a surprising choice of material for a first feature, “Don Jon” is a hilarious movie about relationships. It just happens to feature a hot-head pornography addict as its title character.

Jon (Gordon-Levitt), known as Don Jon to his friends, confesses at the beginning of the film that a normal week for him includes copious amounts of sex and masturbation. Unlike Steve McQueen’s “Shame,” another movie about sex addiction, “Don Jon” doesn’t allow the emotional isolation of addiction to get in the way of the comedy. It also avoids falling into cruder forms of humor often associated with porn.

Jon prides himself on his simple tastes and his highly structured life. He works out and cleans his apartment daily, goes to church with his family on Sunday, hangs out with the guys and romances the ladies on the weekend and, most importantly, masturbates to porn four to 10 times per day. Jon’s explanation of why he prefers porn to regular sex is one of the best scenes in the movie because Gordon-Levitt delivers it in such a serious and deluded way that it is both funny and heart-wrenching at the same time.

The main action of the movie follows Jon’s romance with Barbara (Scarlett Johansson), an Italian-accented bombshell who immediately upsets Jon’s structured life — she’s not a fan of the porn habit. Barbara consumes Hollywood romantic comedies with the same engagement with which Jon consumes his porn. The two characters look to a fictionalized picture of romance and sex to fill an emotional void. Jon and Barbara are superficial, a characteristic most apparent during a huge argument about cleaning supplies.

The cast holds some welcome surprises. Julianne Moore appears halfway through the movie as a fellow student in Jon’s night class who introduces him to some harsh realities about his favorite past time. “Short-Term 12’s” Brie Larson also has a small role as Jon’s sister who communicates mostly through sarcastic eye-rolls. But the standout performance comes from Levitt himself. He does not play Jon as anything more than a horny meathead, but his commitment to the part — right down to the sleeked back, buzzed-on-the-sides haircut — brings the movie together through sheer presence.

Actors-turned directors usually stick to familiar territory when making their first efforts behind the cameras. Clint Eastwood began his directing career with westerns like “The Outlaw Josey Wales”. Ben Affleck made two Boston-set crime flicks before moving on to “Argo.”

While it is unclear what LA-native Gordon-Levitt found familiar in this “Jersey Shore”-themed romance, “Don Jon” is one of those rare comedies that manages to carry emotional weight without ever letting up on the laughs. It handles adult sexual relationships and pornography in a way that is not parody or mockery, while also not being too serious to eliminate opportunities for humor. Overall, Gordon-Levitt delivered a solid first feature with “Don Jon,” and anticipations are high for his next directing venture.